1. Field of the Invention
The present invention relates to a communication apparatus, an electronic apparatus including such a communication apparatus, and an imaging apparatus.
2. Description of the Related Art
The PCI Express (registered trademark) interface is being proposed as the next generation high speed serial interface succeeding the PCI bus scheme (e.g., see “Outline of the PCI Express Standard,” Takashi Satomi, Interface, July 2003).
According to the PCI Express standard, a serial communication circuit is provided in a communication device corresponding to an end point or a Root Complex. The serial communication circuit includes a transmission circuit for transmitting packet data and a reception circuit for receiving data. The transmission circuit includes a transmission buffer for buffering transmission data, and the reception circuit includes a reception buffer for buffering reception data.
In such a communication device conforming to the PCI Express standard, it is difficult to set suitable storage capacities for the transmission buffer and the reception buffer. Specifically, if the storage capacities of these buffers are arranged to be relatively small, transmission and reception of data may be hindered and the performance of the communication device may be degraded. On the other hand, when the storage capacities of the buffers are arranged to be relatively large, large-capacity storage devices have to be used thereby leading to an increase in fabrication cost.
The storage capacities of the buffers are preferably arranged to be large so as to increase the versatility of the communication device. However, increasing the storage capacities of the buffers leads to an increase in fabrication cost as is described above. Thus, it is not suitable to fix the storage capacities of the transmission buffer and the reception buffer included in the communication device.